KR101385815B1 - Organic vapor sorbent protective device with thin film indicator - Google Patents

Abstract

Adsorption media protection devices include an enclosure having a gas inlet, a gas outlet, and a thin film multilayer indicator. The thin film multilayer indicator is close to an adsorption medium capable of adsorbing vapor of interest flowing from the gas inlet toward the gas outlet. The indicator includes a porous detection layer that varies in optical thickness in the presence of the vapor, positioned between the reflective layer and the semireflective layer that is permeable to the vapor. Equilibrium at the vapor concentration applied between at least a portion of the medium and the vapor, the detection layer optics sufficient to cause a visually discernible change in indicator appearance when the vapor passes through the reflective layer into the detection layer and viewed through the antireflective layer. The thickness can be changed.

Adsorption medium, respirator, indicator, enclosure, vapor, infiltration

Description

Organic vapor adsorption protection device with thin film indicator {ORGANIC VAPOR SORBENT PROTECTIVE DEVICE WITH THIN FILM INDICATOR}

The present invention relates to an organic vapor adsorption protection device.

Various chemical, optical or electronic indicators have been proposed to warn users of disposable personal respirators, powered air purifying respirators, protective clothing and other protective devices for the presence of unwanted materials. For example, an End-of-Service Life Indicator ("ESLI") may warn that filter elements in such devices may be nearing saturation or may be invalid for certain materials. Patents and applications relating to personal protection or respiratory protection (and in some cases generally sensors or indicators or in particular ESLI) are described in US Pat. Nos. 1,537,519 (Yablick), 3,966,440 (Roberts), 4,146,887 (Magnante), 4,154,586 (Jones, etc.), 4,155,358 (McAllister, etc.), 4,326,514 (Eian), 4,421,719 (worms) Burleigh), 4,530,706 (Jones), 4,597,942 (Meathrel), 4,684,380 (Leichnitz), 4,847,594 (Stetter), 5,297,544 (May (May et al.), 5,323,774 (Fehlauer), 5,376,554 (Vo-Dinh), 5,512,882 (Sterter et al.), 5,666,949 (Debe et al. 949), 5,659,296 (Deve et al. '296), 6,375,725 B1 (Bernard et al.), 6,497,756 B1 (Curado et al.) And 6,701,864 B2 (Watson, Jr. et al.); US Patent Application Publication Nos. 2004/0135684 A1 (Steinthal et al.), 2004/0189982 A1 (Galarneau et al.), 2004/0223876 A1 (Kirollos et al.) And No. 2005/0188749 A1 (Cooster et al.); And PCT Patent Application Publication WO 2004/057314 A2.

Summary of the Invention

) 등) 및 제6,248,539호(가디리(Ghadiri) 등); 미국 특허 출원 공개 제2004/0184948 A1호(라코브(Rakow) 등); 및 미국 법정 발명 등록 제H1470호(에윙(Ewing) 등)를 포함한다.Other patents and patent applications relating to sensors or indicators other than ESLI are described in US Pat. Nos. 5,611,998 (Aussenegg et al.), 5,783,836 (Liu et al.), 6,007,904 (Schwotzer et al.). No. 6,130,748 (Kruger (

) And 6,248,539 (Ghadiri et al.); US Patent Application Publication No. 2004/0184948 A1 (Rakow et al.); And US Statutory Invention Registration H1470 (Ewing et al.).

Some of the aforementioned sensors or indicators have drawbacks such as the need for electronic devices and power, undesirably complex or expensive designs, insufficient sensitivity or sensitivity to only one or several materials. In addition, although some sensors or indicators are disclosed that can be used to detect liquids or vapors, they are not disclosed to be useful for detecting a range of adsorption by solids.

The present invention provides in one aspect a protective device comprising an enclosure comprising a gas inlet, a gas outlet and a thin film multilayer indicator,

A) The enclosure comprises an adsorption medium capable of adsorbing vapor of interest flowing from inlet to outlet;

B) thin film multilayer indicator,

i) a porous detection layer whose optical thickness varies in the presence of vapor,

ii) a semireflective layer visible from outside the enclosure and not penetrated by vapor;

iii) a reflective layer permeable to vapor, the porous detection layer being located between the semireflective layer and the reflective layer,

C) The reflective layer is an equilibrium at the vapor concentration applied between at least a portion of the medium and the vapor, so that the indicator appearance is visually discernable when the vapor passes through the reflective layer into the detection layer and viewed through the antireflective layer. It is close enough to the medium to be able to change the detection layer optical thickness sufficiently to cause it.

In another aspect, the present invention provides a method for manufacturing a protective device, the method

A) Enclosure-The enclosure is

i) a space for containing an adsorption medium for adsorbing vapor of interest flowing through the enclosure; And

ii)

a) a porous detection layer whose optical thickness varies in the presence of vapor,

b) a semireflective layer visible from outside the enclosure and not penetrated by steam;

c) providing a reflective layer permeable to vapor, wherein the porous detection layer comprises a thin film multilayer indicator positioned between the semireflective layer and the reflective layer;

B) Equilibrium at the vapor concentration applied between at least a portion of the medium and the vapor, sufficient to detect that the indicator appearance will produce a visually discernable change as the vapor passes through the reflective layer into the detection layer and viewed through the antireflective layer Positioning the media in the enclosure close enough to the reflective layer to vary the layer optical thickness; And

C) sealing the enclosure.

The disclosed thin film multilayer indicator can penetrate from the reflective layer side and provide a distinguishable colorimetric change from the semi-reflective layer side. This allows the detection of solvent vapors while the indicator is in contact with or near a solid adsorption medium, such as porous carbon media, which is commonly employed in disposable personal respiratory cartridges. The indicator can provide a change in the appearance of the indicator (e.g. colorimetric changes) that is easily visually distinguishable and reliable, without requiring a powered light source, optical detector or spectroscopic analyzer when the medium is in equilibrium with the vapor. have. Indicators can provide advantages including low cost, ease of use, toughness, and broad spectral sensitivity to various vapors of interest.

These and other aspects of the invention will be apparent from the detailed description below. In no case, however, should the above summary be construed as a limitation on the subject matter of the invention, which is limited only by the appended claims, which may be amended during the filing process.

1 is a perspective view of a respirator in which a replaceable adsorption cartridge has a thin film multilayer end of life indicator.

FIG. 2 is a partial side cross-sectional view of a carbon filled replaceable cartridge for use in the respirator of FIG. 1. FIG.

3 is a partial cross-sectional perspective view of a disposable personal breathing apparatus with a thin film multilayer end of life indicator.

4 is a schematic cross-sectional view of a thin film multilayer indicator.

5A and 5B are schematic side cross-sectional and plan views, respectively, of a thin film multilayer indicator precursor coated with perforated photoresist;

6A and 6B are schematic side cross-sectional and plan views, respectively, of the precursors of FIGS. 5A and 5B after the aluminum reflective layer has been drilled by etching and the photoresist removed.

7-9 are schematic side cross-sectional views of the disclosed thin film multilayer indicator mounted in proximity to various adsorption media.

10-12 are graphs illustrating the response of various thin film multilayer indicators to toluene intrusion.

13 is a photomicrograph of a laser ablation hole through an aluminum reflective layer and a polymer detection layer.

14-17 are graphs showing the response of additional thin film multilayer indicators to toluene intrusion.

18 and 19 are black and white renderings of colored wavefronts moving across a thin film multilayer indicator.

20 is a graph showing the response of a thin film multilayer indicator to intrusion from various vapors.

The terms to be described below are defined as follows.

"Vapor of interest" means organic or inorganic vapor that requires removal from ambient air (eg, breathing air).

"Analyte" means a particular vapor or other component of interest that is detected, such as in a chemical or biochemical assay.

“Light responsiveness” when used with an article or detection layer, such that the article or detection layer is such that the optical thickness (ie, physical thickness or refractive index), reflectance, phase shift, polarization, birefringence, or change in light transmission When present, it means to show a change in the response of the detectable optical properties.

"Enclosures" are cartridges, capsules, pouches, which may be employed to incorporate an adsorptive medium and, if necessary, be sealed for storage or transportation, and subsequently to be opened for installation and use and then to adsorb the vapor of interest. By compartment, housing or other structure.

“Reflective” when used for a layer means that the layer reflects visible light.

A "reflective layer", with respect to the second reflecting layer, has a lower reflectance and a larger light transmittance than the second reflecting layer and can be used in a spaced apart relationship with respect to the second reflecting layer, for example to provide an interference color. Means a first reflective layer.

“Vapor permeability” refers to an air stream containing 1000 ppm of styrene monomer vapor, where one side is used for a reflective layer in fluid communication with the porous detection layer, the other side of the reflective layer flows at 20 l / min for 15 minutes. When exposed, it means that sufficient styrene monomer passes through the reflective layer so that a photoresponsive change occurs in the detection layer.

By "porous" is meant that when used for a material, the material comprises a connected network of pores (which may be, for example, openings, gap spaces or other channels) throughout its volume.

"Size" when used for pores means the length of the longest chord on the cross section, which may be configured for a pore diameter in the case of pores with a circular cross section, or across pores having a non-circular cross section.

"Microporous" when used for a material means that the material is porous with an average pore size of about 0.3 to 100 nanometers.

"Continuous" when used for a layer of material, means that the layer is nonporous and not vapor permeable.

"Semicontinuous" when used for a layer of material, means that the layer is porous and vapor permeable.

“Discontinuous” when used for a layer of material, means that at least two separate and separated islands of material having a void space between within a given plane, or at least two separations with material between within a given plane It is meant that the layers are vapor permeable and have empty spaces separated by them.

The disclosed device can be used to detect vapors of various interests. Representative vapors of interest include water vapor, gases, and volatile organic chemical compounds. Representative organic compounds include alkanes, cycloalkanes, aromatic compounds, alcohols, ethers, esters, ketones, halocarbons, amines, organic acids, cyanates, nitrates, and nitriles such as n-octane, cyclohexane, methyl ethyl ketone, acetone , Ethyl acetate, carbon disulfide, carbon tetrachloride, benzene, styrene, toluene, xylene, methyl chloroform, tetrahydrofuran, methanol, ethanol, isopropyl alcohol, n-butyl alcohol, t-butyl alcohol, 2-ethoxyethanol, acetic acid, Substituted or unsubstituted carbon compounds including 2-aminopyridine, ethylene glycol monomethyl ether, toluene-2,4-diisocyanate, nitromethane, and acetonitrile.

Referring to FIG. 1, the personal respirator 1 includes a face mask 2 mounted with a pair of replaceable air purifying respirator cartridges 3. The cartridges 3 each serve as an enclosure for the adsorption material (eg activated carbon) not shown in FIG. 1. The front cover 4 of each cartridge 3 serves as ambient air through the adsorbent material from the external environment and as an inlet to the gas mask and face mask 2 from the cartridge 3 (not shown in FIG. 1). A plurality of openings 5 serving as gas inlets, which allow flow into the cartridge 3 through the passage. The side wall 6 in each cartridge 3 includes a transparent viewing port 7 through which the wearer of the face mask 2 can see the thin film multilayer indicator 8. Each indicator 8 may wrap around one or more curved areas within the cartridge 3 to provide improved visibility from various viewing angles and allow the cartridge 3 to be mounted on each side of the respirator 1. have. The indicator 8 is optically responsive, undergoing visually distinguishable colorimetric changes when the adsorbent material is in equilibrium with the vapor in the exposed state, thus helping the wearer to recognize when to replace the cartridge or cartridges 3. . The exhaled air exits the respirator 1 through the exhalation valve 9. Indicators can be used in various respiratory protection devices. For example, the indicator may also be disposed within a single cartridge respirator or a powered air purifying respirator.

2 is a partial side cross-sectional view of the respirator cartridge 3. If necessary, the opening 5 can be sealed until use, for example using a removable cover (not shown in FIGS. 1 and 2) which is removed before use. The bed of adsorbent material 21 absorbs or adsorbs the vapor of interest passing from the opening 5 to the outlet 23. The one-way intake valve 25 mounted on the pillar 27 prevents exhaled air from entering the cartridge 3. Screwed or preferably bayonet shaped connectors or connectors 29 may be used to removably couple the cartridge 3 to the mask 2. The side wall 6 comprises a transparent viewing port 7 above the thin film multilayer indicator 8. The port 7 allows ambient light to pass into the indicator 8 through a semireflective layer (not shown in FIG. 2) in the indicator 8 located adjacent to the viewing port 7. If desired, removable or replaceable shields or other covers (not shown in FIG. 2) may optionally be used to protect the port 7 from paint or foam overspray, dust, or other barriers. Ambient light entering the port 7 and the indicator 8 is directed to the observation port 7 by a vapor permeable reflective layer (not shown in FIG. 2) in the indicator 8 located adjacent to the adsorbent material 21. Is returned through. The cartridge 3 has a visually distinguishable change in the appearance of the indicator 8 (eg, a color change such as green to red, the appearance or disappearance of a color such as white or black to colored or colored to white or black, Or from white to black or black to white) is removed and replaced with a new cartridge 3 when indicating that the adsorbent material 21 under the indicator 8 is in equilibrium with the vapor in the exposed state. . By configuring the indicator 8 to cover the entire length of the vapor flow path, an appearance change (eg, color change) "wave surface" will advance with the flow of steam through the indicator 8 through the adsorbent material 21. . The advancing appearance change wavefront may be used only, rather than at the end of its service life, in particular if proper care is taken to design the cartridge 3 so that its remaining life is linearly proportional to the penetration of the spatial vapor wave through the indicator 8. The remaining service life for the cartridge 3 will be indicated, such as gauge or fuel gauge. Alternatively, the indicator 8 may be positioned towards the end of the flow path only to provide a warning only at the desired residual service life percentage. The indicator 8 or observation port 7 may include a pattern or reference color if necessary to assist in visual division of the appearance change of the indicator 8. As explained, the appearance change of the indicator 8 can be visually monitored under ambient lighting. Alternatively, the indicator 8 may be illuminated using an external light source such as a light emitting diode (LED) and evaluated using a photodetector mounted on the periphery of the cartridge 3 to provide an optoelectronic signal. Whether observed by ambient light or by using an external light source and photodetector, the width of the chemical detection can be increased in various ways if necessary. For example, a small array of indicators that cross the vapor flow path can be employed. Each indicator is characterized by a different porous detection layer material (eg, silica detection layer, detection layer applied by plasma activated chemical vapor deposition ("PCVD"), and polymer having intrinsic microporosity ("PIM"). Detection layers, all of which are described below). In addition, the series of indicators may include the same detection layer material (eg, silica) that has been treated using a series of different chemical treatments to provide a range of adsorptive properties. Porous silica can be treated with various alkyl silanes, for example, to impart more hydrophobic properties to the pores.

3 shows a disposable personal respirator 30 in partial cross-sectional view. The device 30 may be a disposable mask, such as shown in US Pat. No. 6,234,171 B1 (Springett et al.), Modified to include a thin film ESLI, for example. The device 30 has a generally cup-shaped shell or respirator body 31 made of an outer cover web 32, adsorptive particles 33 and an inner cover web 34. Welded edges 35 hold these layers together and provide a face seal area to reduce leakage past the edges of the device 30. Leakage is further reduced by a flexible ultra-soft metal nose band 36 of metal, such as aluminum. The device 30 includes a thin viewing multilayer indicator 38 adjacent to a transparent viewing port 37 and adsorbent particles 33. The device 30 also includes an adjustable head and neck strap 39 and an exhalation valve 41 fastened to the device 30 by tabs 40. Further details regarding the construction of such respirators will be familiar to those skilled in the art.

4 shows a schematic view of the thin film multilayer indicator 42 adjacent the transparent substrate 43 and the adsorption medium 48. Indicator 42 includes a semireflective layer 44, a porous detection layer 45 and a vapor permeable reflective layer 46. At or shortly after the equilibrium of the vapor concentration applied between at least a portion of the medium 48 and the vapor of interest, the vapor may pass through the pores 47 into the detection layer 45. The detection layer 45 is made of a suitable material or of a suitable structure such that the optical thickness of the layer changes (eg, increases) upon exposure to the vapor of interest. The resulting optical thickness change results in a visually perceptible appearance change in the indicator 42. The change can be observed from the outside, ie by looking at the indicator 42 through the substrate 43. Some of the ambient light represented by the light rays 49a passes through the substrate 43, is reflected from the semi-reflective layer 44 as light rays 49b, moves back through the substrate 43, and then the substrate 43. Pass outside. Another portion of the ambient light 49a passes through the substrate 43, the semireflective layer 44, and the detection layer 45 and is reflected from the reflective layer 46 as light ray 49c. Light ray 49c travels back through detection layer 45, semi-reflective layer 44 and substrate 43, and then passes out of substrate 43. If an appropriate initial or changed thickness has been selected for the detection layer 45 and the layers 44 and 46 are sufficiently flat, then an interference color is created or extinguished in the light beams, such as the indicator 42 and the light beams 49b and 49c, Visually distinguishable changes in the appearance of (42) will be apparent when observing through the antireflective layer 44. Thus, external equipment such as powered light sources, optical detectors or spectroscopic analyzers will not be required to assess the condition of the indicator 42, but such external equipment can be used if necessary.

The disclosed apparatus can employ a variety of adsorptive media. The adsorption medium will be able to adsorb the vapor of interest that is expected to be present under the intended use conditions. The adsorption medium is preferably porous enough to allow rapid flow of air or other gas therethrough, and may be finely divided solids (eg, powders, beads, flakes, grains or agglomerates) or porous solids (eg, open cell foams). It may be in the form of. Preferred adsorptive media materials include activated carbon; Alumina and other metal oxides capable of removing the vapor of interest by adsorption; Clay and other minerals treated with an acidic solution such as acetic acid or an alkaline solution such as aqueous sodium hydroxide; Molecular sieves and other zeolites; Other inorganic adsorbents such as silica; And (see, for example, VA Davankov and P. Tsyurupa, Pure and Appl. Chem., Vol. 61, pp. 1881-89 (1989)) and LD Belyakova, TI Schevchenko, VA Davankov and MP Tsyurupa, Supercrosslinks such as highly crosslinked styrenic polymers known as "Styrosorbs" (as described in Adv. In Colloid and Interface Sci. Vol. 25, pp. 249-66, (1986)). Organic adsorbents comprising a binding system. Activated carbon and alumina are particularly preferred adsorption media. Mixtures of adsorptive media can be employed, for example, to absorb a mixture of vapors of interest. In the finely divided form, the adsorbed particle size can vary greatly and will usually be selected based in part on the intended use conditions. As a general guideline, the finely divided adsorbent media particles can vary in size to an average diameter of about 4 to about 3000 micrometers, such as an average diameter of about 30 to about 1500 micrometers. Mixtures of adsorption media particles having different size ranges (eg, in a bimodal mixture of adsorption media particles, or in a multilayer arrangement employing larger adsorption particles in the upstream layer and smaller adsorption particles in the downstream layer) may also be used. It may be employed. U.S. Patent Nos. 3,971,373 (Braun et al.), 4,208,194 (Nelson) and 4,948,639 (Brooker et al.) And U.S. Patent Application Publication No. 2006/0096911 A1 (Brey) Adsorption media may also be employed in combination with a suitable binder (eg, bonded carbon) or captured on or within a suitable support.

The indicator can be rigid or flexible. The flexible indicator can preferably be flexed sufficiently without breaking so that it can be produced using one or more roll processing steps and, if necessary, in use, around the center of the adsorption medium enclosure, for example as shown in FIG. Can be bent. Indicators may be attached to the filter housing or other support using a variety of techniques, including films or mass adhesives, mechanical inserts, thermal bonding, ultrasonic welding, and combinations thereof.

The substrate is optional, but when present, it can be made of a variety of materials that can provide a support that is suitably transparent to the thin film indicator. The substrate can be rigid (eg, glass) or flexible (eg, a plastic film that can be handled in one or more roll processing steps). If made of a flexible material such as a suitably transparent plastic, the substrate preferably has a vapor permeability low enough that the vapor (s) of interest are not permeated into or out of the detection layer through the antireflective layer. If the substrate is omitted, the antireflective layer should be sufficiently impermeable to prevent or prevent such vapor permeation. If desired, a porous substrate can be positioned between the reflective layer and the adsorption medium. For example, vapor of interest may be allowed to pass from the adsorption medium through the permeable substrate and the reflective layer into the detection layer.

The semi-reflective and reflective layers can be made of various materials that can cooperate when respectively spaced apart to provide diffuse or preferably specular light reflection and to provide a visually easily recognizable indicator appearance change. Suitable semireflective and reflective layer materials include metals such as aluminum, chromium, gold, nickel, silicon, silver, palladium, platinum, titanium and alloys containing such metals; Metal oxides such as chromium oxide, titanium oxide and aluminum oxide; And US Pat. Nos. 5,699,188 (Gilbert et al.), 5,882,774 (Jonza et al.) And 6,049,419 (Wheatley et al.), And PCT Application Publication WO 97/01778 (Oderkirk). Multilayer optical films (including birefringent multilayer optical films) described in (Ouderkirk et al.). The semireflective and reflective layers can be the same or different. Metal nanoparticle coatings (eg, metal nanoparticle inks) may be employed to form reflective layers, as described in co-pending US patent application Ser. No. 11 / 530,619, entitled 'Intrusive Nanoparticle Reflector'. .

The antireflective layer is less reflective than the reflective layer and transmits some incident light. The semireflective layer can have, for example, a physical thickness of about 2 to 50 nm, a light transmittance at 500 nm of about 20 to about 80%, and a reflectance at 500 nm of about 80 to about 20%. The semi-reflective layer itself may be impermeable to vapor and (if so preferably continuous), may be selectively coated on or adjacent to a suitable substrate. The semireflective layer may also be permeable to steam (if so, for example, discontinuous or semicontinuous) and may be coated on or adjacent to a suitable vapor impermeable substrate. The plane of the semireflective layer adjacent to the detection layer is preferably flat within about ± 10 nm.

The reflective layer can, for example, have a physical thickness of about 1 to about 500 nm, a light transmittance at 500 nm of about 0 to about 80%, and a reflectance at 500 nm of about 100 to about 20%. The reflective layer is preferably porous, patterned, discontinuous, semicontinuous or otherwise sufficiently permeable to allow vapor to pass from the adsorption medium through the reflective layer into the detection layer. Desired porosity or discontinuity can be achieved through suitable deposition techniques or through appropriate post-deposition treatments such as selective etching, reactive ion etching or patterned laser ablation. The reflective layer may also be formed by depositing a vapor permeable metal nanoparticle layer as described in co-pending US patent application Ser. No. 11 / 530,619 described above to form a vapor permeable layer of filled nanoparticles, the pores being nano Provided by the gap between the particles. If desired, discontinuities can be formed in the reflective layer in a pattern of shapes, letters, symbols, or messages. This may cause a distinguishable pattern to appear or disappear upon exposure to the vapor (s) of interest. The observer may find it easier to distinguish the contrast color of such a pattern than to distinguish the colorimetric changes of the entire indicator film.

The detection layer mixture can be homogeneous or heterogeneous and can be made, for example, of a mixture of inorganic components, a mixture of organic components, or a mixture of inorganic and organic components. Detection layers made of a mixture of components can provide improved detection of analyte groups. The detection layer preferably has a range of pore sizes or surface areas selected to provide vapor adsorption properties similar to the adsorption medium. Suitable porosity can be obtained by using a porous material, such as a foam made of a high internal phase emulsion, such as described in US Pat. No. 6,573,305 B1 (Thunhorst et al.). Porosity can also be achieved through carbon dioxide foaming (see "Macromolecules", 2001, vol. 34, pp. 8792-8801) to produce microporous materials, or by nanophase separation of polymer blends ("Science", 1999, vol. 283, p. 520). In general, the pore diameter is preferably smaller than the peak wavelength of the desired indicator color. Nano-sized pores having an average pore size of, for example, about 0.5 to about 20 nm, 0.5 to about 10 nm, or 0.5 to about 5 nm are preferred.

Representative inorganic detection layer materials include porous silica, metal oxides, metal nitrides, metal oxynitrides, and other inorganic materials that may be formed into a transparent porous layer of a thickness suitable to produce color or colorimetric changes by optical interference. For example, the inorganic detection layer material may be silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, titanium oxide, titanium nitride, titanium oxynitride, tin oxide, zirconium oxide, zeolite, or a combination thereof. Porous silica is a particularly preferred inorganic detection layer material because of its toughness and compatibility with wet etching treatment.

Porous silica can be prepared, for example, using a sol-gel treatment route and can be prepared with or without an organic template. Exemplary organic templates include anionic or nonionic surfactants such as surfactants such as alkyltrimethylammonium salts, poly (ethyleneoxide-co-propylene oxide) block copolymers and other surfactants or polymers that will be apparent to those skilled in the art. The sol-gel mixture can be converted to a silicate and the organic template can be removed leaving a network of micropores in the silica. Representative porous silica materials are described in Ogawa et al., Chem. Commun. pp. 1149-1150 (1996), in Kresge et al., Nature, Vol. 359, pp. 710-712 (1992), Jia et al., Chemistry Letters, Vol. 33 (2), pp. 202-203 (2004) and US Pat. No. 5,858,457 (Brinker et al.). Various organic molecules can also be employed as the organic template. For example, sugars such as glucose and mannose can be used as organic templates for producing porous silicates (see Wei et al, Adv. Mater. 1998, Vol. 10, p. 313 (1998)). Organic substituted siloxanes or organic bis-siloxanes can be included in the sol-gel composition to make the micropores more hydrophobic and limit the adsorption of water vapor. Plasma chemical vapor deposition may also be employed to create the porous inorganic detection material. Such methods generally include forming an analyte detection layer by forming a plasma from a gaseous precursor, depositing a plasma on the substrate to form an amorphous random shared network layer, and then forming a microporous amorphous random shared network layer. Heating the amorphous shared network layer to form. Examples of such materials are described in U.S. Patent No. 6,312,793 (Grill et al.) And US patent application Ser. No. 11 / 275,277 filed December 21, 2005, entitled 'Plasma Deposition Microporous Analyte Detection Layer'. It is described in the issue.

Representative organic detection layer materials include hydrophobic acrylates and methacrylates, difunctional monomers, vinyl monomers, hydrocarbon monomers (olefins), silane monomers, fluorinated monomers, hydroxylated monomers, acrylamides, anhydrides, aldehyde-functional monomers, Polymers prepared or preparable from the class of monomers including amine- or amine salt-functional monomers, acid-functional monomers, epoxide-functional monomers and mixtures or combinations thereof, copolymers (including block copolymers), and their Mixtures. U.S. Patent Application Publication No. 2004/0184948 A1, supra, contains a comprehensive list of such monomers, see further details for further details. Polymers having intrinsic microporosity as described above (PIM) provide particularly preferred detection layers. PIM is typically a nonnetworked polymer that forms a microporous solid. Due to the typically high stiffness and twisted molecular structure, the PIM cannot fill the space efficiently, providing the disclosed microporous structure. Suitable PIMs are described in "Polymers of intrinsic microporosity (PIMs): robust, solution-processable, organic microporous materials," Budd et al., Chem. Commun., 2004, pp. 230-231, including but not limited to polymers. Additional PIMs are described by Buddha et al., J. Mater. Chem., 2005, 15, pp. 1977-1986, McKeown et al., Chem. Eur. J. 2005, 11, No. 9, 2610-2620 and PCT Publication WO 2005/012397 A2 (McKeown et al.).

One or more polymers in the organic detection layer may be at least partially crosslinked. Crosslinking may be desirable in some embodiments because it can increase mechanical stability and sensitivity to certain analytes. Crosslinking involves the incorporation of one or more multifunctional monomers into the detection layer, subjecting the detection layer to electron beam or gamma ray treatment, for example by adding or forming a coordination compound or an ionic compound in the detection layer, or hydrogen bonding within the detection layer. Can be achieved. In one exemplary embodiment, crosslinking is performed in the presence of a porogen that can then be extracted from the crosslinked system to produce a porous detection layer. Suitable porogens include but are not limited to inert organic molecules such as normal alkanes (eg decane) or aromatics (eg benzene or toluene). Other crosslinked polymers include the highly crosslinked styrenic polymers described above.

If desired, the detection layer material can be treated to modify its surface or adsorption properties. Various such treatments can be employed, for example, by exposing the micropores of the inorganic detection layer to a suitable organosilane compound. The detection layer may, in addition or instead, be treated with a suitable adhesion promoting material (eg, a binding layer made of titanium or other suitable metal) to promote adhesion between the semireflective or reflective layer and the detection layer. Such treatment may also be applied to the semi-reflective or reflective layer to enhance adhesion to the detection layer.

In many applications, the detection layer is preferably hydrophobic. This will reduce the likelihood that water vapor (or liquid water) will cause a change in the optical thickness of the detection layer to interfere with the detection of the analyte, for example the detection of organic solvent vapors.

The detection layer can be made from a single layer or from two or more sublayers. The lower layers can have various configurations. For example, they can be arranged side by side or stacked. Sublayers may also be made of different materials selected to absorb different vapors of interest. One layer or a set of sublayers may be discontinuous or patterned. The pattern may generate or remove colored images, words, or messages upon exposure to the analyte, to provide a user with easily identifiable alerts. The layer or sublayer pattern can also be formed by providing one or more portions that react to a particular analyte and one or more portions that do not react to the same analyte. The pattern of reactive material can also be deposited on a larger non-reactive sublayer, such as by making the patterned layer sufficiently thin so that no difference in optical thickness is visible until the analyte is absorbed. The thickness of the detection layer can also be patterned, for example as described in US Pat. No. 6,010,751 (Shaw et al.). This may allow the pattern to disappear (eg when the thinner portion expands to the same thickness as the thicker portion) or to disappear (eg when the portion shrinks to a smaller thickness than the adjacent portion).

The disclosed apparatus can include additional layers or elements if desired. For example, a porous layer of an adsorbent loading composite (eg, a web in which activated carbon particles are embedded in a matrix of fibrous PTFE as described in US Pat. No. 4,208,194 described above) is positioned between the reflective layer and the adsorption medium, The vapor penetrating into the indicator may be homogenized or otherwise relaxed the indicator response to conditions in the adsorption medium.

The disclosed apparatus can be used for a variety of applications, including organic vapor respirators, powered air purifying respirators (PAPRs), protective clothing, collectable protective filters, and other applications that will be familiar to those skilled in the art.

The invention is further illustrated in the following illustrative examples in which all parts and percentages are by weight unless otherwise indicated. The abbreviations shown in Table 1 below are used in some examples.

Example 1

A multilayer film indicator comprising an impermeable semireflective layer, a porous silica detection layer and a vapor permeable reflective layer was prepared as follows. The glass slides were first sputter coated using a Denton Vacuum Desk II sputter coater equipped with an AuPd (Au / Pd mass ratio of 60:40) target to provide an approximately 5 nm thick semireflective layer. Sputter coating power and coating duration were 35 milliamps and 20 seconds, respectively, under vacuum of 13.3 kPa (100 millitorr). Porous silica films were deposited on the antireflective layer by sol-gel solution dip coating. Silica sol was prepared using a two step hydrolysis process. In step 1, 231.6 parts of tetraethoxysilane, 195.2 parts of pure ethanol, 17.28 parts of deionized water and 0.715 parts of 0.07N HCl were combined in a vessel and stirred with heating at 60 ° C. for 90 minutes to form a silica sol. In step 2, 122.97 parts of step 1 silica sol, 17.50 parts of 0.07 N HCl and 5.75 parts of deionized water were combined in a beaker and stirred for 15 minutes without external heating. The resulting sol-gel solution was stirred for an additional 15 minutes while heating to 50 ° C. and then diluted with 263.32 parts of pure ethanol. The coating solution comprising ethyl cellulose was prepared using 25.25 parts of step 2 sol-gel solution, 25.00 parts of isopropyl alcohol and 1.71 parts of ETHOCEL ™ Standard 20 Premium (from Dow Chemical Company). Premium) Ethyl cellulose was combined and prepared by stirring overnight (16 h) in a covered container to completely dissolve the ethyl cellulose.

Glass slides coated with AuPd were dip coated in a coating solution using a 10 cm / min draw rate in an enclosure maintained at a relative humidity of less than 30% to prevent moisture condensation during the coating process. It applied a sol-gel coating on both sides of the slide. Since the coating was transparent, the coating on one side could be used to make a porous detection layer, and the coating on the other side could be allowed to remain on both sides, remaining on the final viewing surface. The coated sample was dried in a humidity controlled enclosure for 2 minutes. The coated slides were then heated in a belt furnace at 400 ° C. using a 30 minute heating cycle including 11 minutes of heating time, 8 minutes of holding time at 400 ° C., and 11 minutes of cooling time. To ensure complete dehydration and pyrolysis of the organics, the slides were subjected to a 13 hour heating cycle including a 2 hour heating time to 400 ° C., a 1 hour holding time at 400 ° C., and a 10 hour cooling time to return to room temperature. It was reheated in the air atmosphere box furnace used. The silica layer on one side of the slide was then subjected to a CHA Industries Mark-50 evaporation coater operating at a base pressure of 0.0013 kPa (1 × 10 ⁻⁵ Torr), From Cerac, Inc. T-2003 99.995% pure vacuum deposition grade 6 mm x 6 mm for pellets and aluminum layers (also from Cerac, Inc.) No. A-2049 99.99% pure vacuum deposition grade 6 mm × 6 mm pellets were used to coat 10 nm thick Ti binding layers and 100 nm thick aluminum reflector layers.

A photolithography process by wet chemical etching was employed to make the aluminum reflective layer vapor permeable. Hexamethyldisilazane adhesion promoter (from JT Baker) was spin coated onto an aluminum layer at 2500 rpm and then PR 1813 positive (from Shipley, LLC). A spin coating layer of photoresist was applied at 4000 rpm to give a 1.3 micrometer thick film. The photoresist was baked at 96 ° C. for 30 minutes and then exposed to UV light for 9 seconds, with a UV intensity of 14 kW / cm 2, through a photomask on two sections of the slide. The first section employed a low etch photomask with a regular array of holes of 3 micrometer diameter spaced at 10 micrometer pitch. The second section employed a high etch photomask with a regular array of 3 micron holes spaced at a 5 micron pitch. After exposure, the slides were immersed in the MF319 developer (from Shipley, LC) for 45 seconds and then hardbaked at 120 ° C. for 30 minutes. The developer removed the positive photoresist within the irradiated hole area to provide an article 50 as shown in FIGS. 5A and 5B, where 52 denotes the final thin film multilayer indicator and 53 denotes the indicator 52. Denotes a glass substrate to be observed, 54 denotes an Au / Pd antireflective layer, 55 denotes a porous silica detection layer, 56 denotes an aluminum reflective layer, and 57 denotes a hole in the photoresist 58. Display.

Wet etching of aluminum layer 56 was performed using an acidic etching solution prepared by combining 500 milliliters of concentrated H ₃ PO ₄ , 19.4 milliliters of concentrated HNO ₃ , 96.8 milliliters of concentrated acetic acid, 32.2 milliliters of H ₂ O, and 0.6 milliliters of ethylene glycol. 90 ° C. was performed for 90 seconds. The etched film was immediately rinsed in deionized water. Next, the Ti layer was etched using a basic etching solution prepared by combining 100 milliliters 0.1 M EDTA, 8 milliliters concentrated NH ₄ OH and 20 milliliters 30% H ₂ O ₂ . The etched film was immediately rinsed again in deionized water. Finally, the remaining photoresist 58 is stripped from the aluminum layer 56 using a 1165 remover (also from Sifli, ELC) to complete the thin film multilayer indicator as shown in FIGS. 6A and 6B. 60 is provided, where 66 indicates a vapor permeable aluminum reflective layer and 67 indicates a hole in the aluminum layer 66.

Example  2

The thin film indicator 60 of Example 1 was evaluated using three different vapor paths. The first vapor path is shown in FIG. 7. An organic vapor containing air stream 72 flowed across the indicator 60 above the glass substrate 53. Small pieces of woven carbon paper 74 positioned against vapor permeable aluminum reflective layer 66 allowed the path for organic vapor in air stream 72 to reach porous silica detection layer 55. Incident light rays, such as light ray 76 from light source 77, were reflected by semi-reflective layer 54 as first reflected light 78a and reflected by aluminum layer 66 as second reflected light 78b. . The second vapor path is shown in FIG. 8. FIG. 8 is similar to FIG. 7, but the organic vapor containing air stream 72 reached the porous silica detection layer 55 through a piece of glass wool 84 positioned against the vapor permeable aluminum reflective layer 66. . The third vapor path is shown in FIG. 9. 9 is similar to FIGS. 7 and 8, but the organic vapor-containing air stream 72 reached the porous silica detection layer 55 through a piece of flexible microporous carbon loaded nonwoven web 94. Web 94 is from IROGRAN ™ PS 440- (from Huntsman International LLC), prepared as described in US Patent Application Publication 2006/0096911 A1 (Bray et al.). (Approximately 0.22 g / cc) of 40 × 140 mesh activated carbon particulate derived from coconut shell (from Pacific Activated Carbon Co.) dispersed throughout an elastic fibrous web made of 200 thermoplastic polyurethane Corresponding to an effective carbon density of about 500 g / m 2. Sample spectra were monitored using a white light source, a fiber optic reflection probe, and a spectrometer. FIG. 10 shows a graph of wavelength variation versus ppm toluene intrusion for each vapor path, where curves A, B and C correspond to the vapor paths shown in FIGS. 7, 8 and 9, respectively. As shown in FIG. 10, all three vapor paths provided similar wavelength variations at a given toluene penetration level. Curve C also shows that the indicator 60 maintained its performance when in adsorption competition with the microporous carbon loading web.

If desired, thin film indicator 60 may be illuminated using an external light source, such as a light emitting diode (LED), and evaluated using a photodetector. FIG. 11 shows sample spectra obtained by measuring the initial response (curve A) of thin film indicator 60 to toluene vapor in 50 ppm (curve B) and 2000 ppm (curve C) toluene as a function of wavelength. . FIG. 12 shows a simulation obtained by multiplying the obtained sample spectrum of FIG. 11 by the Gaussian approximation of the LED spectrum and calculating the change in light intensity (in any unit) measured using a suitable photodetector. The signal received by a detector (eg, a PN, PIN, or Avalanche photodiode with a spectral response selected to match the LED wavelength) is measured by integrating the LED / sample spectrum. In the initial signal normalized to 512 counts for the green LED (curve A in FIGS. 11 and 12), the signal detected for the blue LED decreased by any unit of 21 upon exposure to 50 ppm toluene (FIGS. 11 and Curve B) of FIG. 12 indicates that a signal: noise (S / N) ratio of approximately 5: 1 is obtained using standard components. The S / N ratio can be further improved by incorporating a thicker layer of silica in the indicator to narrow the initial sample spectrum. Changes in overall thin film indicator thickness can also be made to optimize the peak shift position for the LED spectral output. Curve C of FIGS. 11 and 12 shows the expected response at 2000 ppm toluene.

In the examples described below, light sources and spectroscopy were used to measure changes in sensor characteristics. However, it will be understood that the disclosed indicators can be easily observed under ambient lighting.

Example 3

Thin film indicators were prepared using an intrinsic microporous polymer (PIM) as the detection layer and a laser to remove pores in the reflection and detection layers.

PIM Polymer Preparation. PIM polymers are generally described in Buddha et al. in Advanced Materials, 2004, Vol. 16, No. 5, pp. 456-459, prepared according to the procedures reported in monomers BC and FA. 9.0 grams of BC were combined with 5.28 g of FA, 18.0 g of potassium carbonate, and 120 milliliters of DMF, and the mixture was reacted at 70 ° C. for 24 hours. The resulting polymer was dissolved in THF, precipitated three times from methanol and then dried under room temperature vacuum. A yellow solid product having a molecular weight (Mw) of 61,800 was obtained.

PIM sample with laser treated holes. Glass slides were sputter-coated with a 5 nm thick Au / Pd layer using a Denton Vacuum Desk II sputter coater from a Denton vacuum with an AuPd target at a 60:40 Au: Pd mass ratio. Sputter coating power and coating duration were 35 milliamps and 20 seconds, respectively, under vacuum of 13.3 kPa (100 millitorr). The PIM polymer was then spin coated onto Au / Pd using a 4% solution of the aforementioned PIM polymer in chlorobenzene coated on the Au / Pd layer at 3000 rpm. Next, using a Mark-50 evaporation coater from CHA Industries operating at a base pressure of 0.0013 kPa (1 × 10 ⁻⁵ Torr) and a metal target in the form of a 6 × 6 mm pellet obtained from Cerrac Inc. A nm layer of aluminum layer was deposited on the PIM polymer. The sample was then laser removed using a femtosecond processing process to create an array of conical holes through the aluminum and PIM polymer layers. The pore diameters close to the aluminum layer were approximately 13 micrometers and they narrowed to about 5 micrometers close to the Au / Pd layer. A micrograph of the laser ablation hole (lighted to make the measurement data easier to see) is shown in FIG. 13.

In order to evaluate the ability of the resulting thin film indicator to compete with the microporous carbon for adsorption of organic vapor, the indicator was charged with the microporous carbon of Example 2 while the vapor permeable aluminum reflective layer was in contact with the web and its microporous carbon. Placed on a small piece of web. Carbon-loaded BMF webs are made from elastomeric fibers made from Igroran PS 440-200 thermoplastic polyurethane (from Huntsman International LLC), prepared as described in US Patent Application Publication No. 2006/0096911 A1 (Bray et al.). 40 × 140 mesh activated carbon fine particles derived from coconut husks (from Pacific Activated Carbon Company), dispersed throughout the web. The fibrous web had an effective fiber diameter of 17 micrometers and a carbon loading level of 500 g / m 2, corresponding to about 0.22 g / m 3 carbon density. When equilibrated with 1000 ppm cyclohexane flowing at 32 L / min, the carbon in this nonwoven web layer adsorbs about 0.21 g of cyclohexane per gram of carbon. As toluene vapor passed through the indicator through the carbon loading layer, the indicator was illuminated using a spectrometer and optical fiber reflecting probe and observed through the glass substrate. A peak signal wavelength shift of about 27 nm was observed (from about 606 nm to about 633 nm), as shown in FIG. 14, where curve A and curve B represent the initial signal and the signal at 50 ppm toluene, respectively. This indicated that the PIM polymer detection layer maintained its adsorption function when in thermodynamic competition with the microporous carbon.

Example 4

Thin film indicators were fabricated using the intrinsic microporous polymer (PIM), Au / Pd antireflective layer, and silver nanoparticle reflective layer as detection layers. Using the method of Example 3, the glass slides were sputter coated with a 5 nm thick Au / Pd layer, followed by spin coating (at 750 rpm) a layer of PIM polymer on the Au / Pd layer. Next, two different indicators were prepared by applying a silver nanoparticle suspension to the PIM polymer layer. Indicator A was prepared using NPS-J silver nanoparticle suspension (60% in tetradecane) from Harima Corporation. Transmission electron microscopy (TEM) analysis of the particles showed a size distribution of approximately 2 to 10 nm diameter. The resulting nanoparticle suspension in an amount of 0.08 g was mixed with 2 milliliters of heptane to provide a diluted suspension containing about 3.3% silver. The diluted suspension was spin coated onto the PIM film at 500 rpm to provide a vapor permeable reflective layer having a reflectance of about 62% at 500 nm for a 100 nm thick aluminum reference layer. Indicator B was prepared using SVE 102 silver nanoparticle suspension (30% in ethanol, 30 nm average particle diameter) from Nippon Paint (America) Corporation. 0.7 g of this as-obtained suspension was mixed with 2 milliliters of ethanol to provide a diluted suspension containing about 9.1% silver. The diluted suspension was spin coated onto the PIM film at 1000 rpm to provide a vapor permeable reflective layer having a reflectance of about 70% at 500 nm for a 100 nm thick aluminum reference layer.

The indicator was evaluated using the method of Example 3 to assess the ability to compete with microporous carbon for adsorption of organic vapors. In Figure 15, curve A and curve B represent the initial signal at indicator A and the signal at 50 ppm toluene, respectively. Similarly, in FIG. 16, curve A and curve B represent the initial signal at indicator B and the signal at 50 ppm toluene, respectively. Indicator A exhibited a peak signal wavelength shift of about 20 nm when invaded by 50 ppm toluene (from about 564 nm to about 584 nm). Indicator B exhibited a peak signal wavelength shift of about 17 nm when 50 ppm toluene invaded (from about 544 nm to about 561 nm). Indicators A and B both retained their adsorption function when in thermodynamic competition with microporous carbon.

Example 5

Using the method of Example 3, PIM polymers were prepared with monomers BC and FA. Using the method of Example 3, a 1 mm thick glass slide was sputter coated with a 5 nm thick Au / Pd layer, followed by spin coating a layer of PIM polymer (at 1500 rpm) on the Au / Pd layer. Using the method of Example 4 (indicator B), the diluted SVE 102 silver nanoparticle suspension was spin coated onto a PIM film to provide a vapor permeable nanoparticle reflective layer. The resulting thin film indicator had a greenish yellow appearance when visually observed through a glass slide. DYMAX ™ No. from Dymax Corporation. The indicator was attached to the inner sidewall of a filtration cartridge made of transparent polycarbonate resin with the OP-4-20641A UV-cured optical adhesive facing the vapor permeable nanoparticle reflective layer towards the cartridge. The cartridge was filled with 45.7 g of activated carbon sorbent. Several small holes were drilled in the cartridge cover upstream just above the indicator to ensure proper vapor flow at the indicator / adsorbent bed interface. The cartridge was infiltrated with 50 ppm toluene in dry air (<3% RH) flowing at 64 L / min. Indicators were monitored through the polycarbonate cartridge body at 50-60% of bed depth using fiber optic reflection probes and Ocean Optics spectroscopy with an illumination spot diameter of less than 1 mm. Between 6 and 16 hours after the start of toluene invasion, the indicator showed a gradual red shift of color totaling 14 nm. Given the position of the indicator within the cartridge, the timing and magnitude of the indicator response is individually obtained using a MULTIRAE ™ IR photoionization detector from RAE Systems Inc. located at the cartridge exit. Consistent with the concentration data collected. Indicator data and IR photoionization detector data are shown in FIG. 17.

The second cartridge was assembled in the same manner and invaded 500 ppm styrene in dry air (<3% RH) flowing at 64 L / min. QX5 ™ computer microscopes from Digital Blue Corporation were angled to initially appear green when the indicator was observed and used to record the appearance of the indicator when styrene vapor was invaded. As the intrusion progressed, the initial green color of the indicator changed to orange along the color change wavefront moving from the cartridge inlet toward its outlet. The RGB histogram of the initial green color recovered the mean values of r = 145, g = 191, and b = 121. After the indicator responded to styrene vapor by changing green to orange, the histogram values were r = 208, g = 179, and b = 127. 18 shows a black and white rendering of the indicator color during the experiment and shows vapor wave progression and appearance. Green and orange visible parts are indicated by the letters G and O, wavefronts by the letter W, and styrene flow direction by the letter S.

Example 6

Using the method of Example 3, PIM polymers were prepared with monomers BC and FA. CHA Industry Mark-50 evaporator operated at a base pressure of 0.0013 kPa (1 × 10 ^-5 Torr) The washed glass slides were metallized into a 10 nm thick semi-reflective Ti layer using T-2003 titanium pellets (99.995% purity, 6 × 6 mm, from Cerac Inc.). A 4% PIM polymer solution in chlorobenzene was spin coated onto the Ti layer at 1000 rpm. Using the method of Example 4 (indicator B), the diluted SVE 102 silver nanoparticle suspension was spin coated onto a PIM film to provide a vapor permeable reflective layer. Following the silver deposition, the film sample was heated in air at 150 ° C. for 1 hour. The resulting thin film indicator had a green appearance when visually viewed through a glass slide. Dymax No. The indicator was adhered to an additional glass slide layer using OP-4-20641A UV-cured optical adhesive. The resulting glass slide stack was adhered to the inner sidewall of a filter cartridge made of transparent polycarbonate plastic. Next, an aqueous polytetrafluoroethylene ("PTFE") particle dispersion was finely prepared using the method described in US Pat. No. 4,153,661 (Ree et al.) And the same method as in Example 1 of US Pat. No. 4,208,194. A dough was formed by combining with activated pulverized activated carbon particles. The dough was milled to dryness but not calendered to provide a composite web in which activated carbon particles were embedded in a matrix of fibrous PTFE. A layer of carbon composite web was attached to the top edge of the glass slide stack and folded down to cover the porous nanoparticle reflective layer. The remaining filter cartridge volume was then charged with 45.8 g of activated carbon sorbent. Several small holes were drilled in the cartridge cover upstream just above the indicator to ensure proper vapor flow at the indicator / adsorbent bed interface. The cartridge penetrated 200 ppm styrene in dry air (<3% RH) at a flow rate of 32 L / min. Using ambient lighting, the TRENDNET ™ model TV-IP201W wireless camera (from TRENDnet Company) is angled to initially appear green when the indicator is observed, and styrene vapors invade When used to record the appearance of the indicator. As the experiment progressed, the indicator color changed from initial green to deep red as the color change first appeared near the filter cartridge inlet and moved towards the cartridge outlet. When the steam flow was stopped, the wavefront became somewhat cloudy but did not move closer to or farther from the cartridge outlet. The initial green RGB histogram recovered the mean values of r = 30, g = 99, and b = 51. After the indicator responded to styrene vapor by changing green to red, the histogram values were r = 97, g = 56, and b = 66. 19 shows black and white rendering of the indicator color during the experiment and shows vapor wave progression and appearance. The carbon adsorbent is indicated by the letter C, the green and red visual indicator portions are indicated by the letters G and R, the wavefront is indicated by the letter W, and the styrene flow direction is indicated by the letter S. The wavefront was significantly more uniform than the wavefront of FIG. 18, including a filter cartridge that did not include a carbon composite web between the indicator and the adsorption medium.

Example 7

Using the method of Example 6, a 10 nm thick titanium semireflective layer was evaporated coated onto the washed glass slide. Next, a Ti-coated glass slide was mounted on the flat electrode. This time, the electrodes were mounted in an aluminum vacuum chamber equipped with a dry mechanical pump and a turbomolecular pump in series with the Roots blower. The chamber was closed and pumped to a base pressure of 0.067 kPa (0.0005 Torr). A mixture of tetramethylsilane, oxygen and butadiene gas was introduced into the chamber at respective flow rates of 100 standard cubic centimeters per minute (sccm), 100 sccm and 160 sccm. By powering the planar electrodes using a model RF50S radio frequency power supply (from RF Power Products) operating over a model AMN3000 impedance matching network (from PlasmaTherm Inc.) A plasma was formed. While the plasma was in operation, the power delivered was maintained at 75 watts and the chamber pressure was maintained at 37 millitorr (4.93 kPa). The deposition was carried out for 14 minutes, producing a plasma deposited organic thin film with a thickness of 0.768 microns. The plasma deposited thin film was annealed in a vacuum furnace at a temperature of 450 ° C. for 1 hour to provide a microporous thin film detection layer over the titanium semireflective layer. Add 2 milliliters of silver nanoink (SILVER NANOINK ™) silver nanoparticle slurry (Lot S Ag 031027W from Advanced Nano Products Co., Ltd.) in 0.0475 g of methanol Dilution with methanol gave a diluted suspension and spin coated at 1500 rpm on a thin film detection layer. The resulting spin coated silver nanoparticle layer was dried to produce a vapor permeable thin film silver nanoparticle reflective layer on top of the thin film detection layer.

To assess the ability of the resulting indicator to compete with microporous carbon for adsorption of organic vapor, the indicator is placed over a small piece of the carbon composite web employed in Example 6, with the permeable reflective layer in contact with the carbon composite web. I was. The color of the sensor was evaluated by observing the indicator appearance through the glass substrate using a spectrometer and a fiber optic reflective probe. The sensor was exposed to toluene, methyl ethyl ketone and ethylbenzene vapor flow through the carbon composite web. Toluene and methyl ethyl ketone streams were maintained at less than 5% relative humidity and ethylbenzene streams were kept at 82% relative humidity. The results are shown in FIG. 20 where curves A, C and D show the methyl ethyl ketone, toluene and ethylbenzene vapor concentrations for the observed wavelength variations, respectively, and curve B was observed when no carbon composite web was employed. Toluene vapor concentration for the shifted wavelength is shown. The results in FIG. 20 show that the disclosed indicators showed wavelength variations of about 6 to 16 nm at 200 ppm vapor concentration and wavelength variations of about 12 to 21 nm at 2000 ppm vapor concentration. Curves B and C also show that the porous detection layer in the disclosed indicators retained their adsorption capacity even when in thermodynamic competition with the microporous carbon.

Example 8

Using the method of Example 3, PIM polymers were prepared with monomers BC and FA. CHA Industry Mark-50 evaporator operated at a base pressure of 0.0013 kPa (1 × 10 ^-5 Torr) Using T-2003 titanium pellets, the washed glass slides were metallized into a 10 nm thick Ti antireflective layer. A 4% PIM polymer solution in chlorobenzene was spin coated onto the Ti layer at 2000 rpm. Using the method of Example 4 (indicator B), the diluted SVE 102 silver nanoparticle suspension was spin coated onto a PIM film and dried under vacuum at room temperature for 12 hours, between the titanium semireflective layer and the vapor permeable metal nanoparticle reflective layer. A multilayer thin film indicator with a PIM detection layer positioned at was provided. The indicator had a green appearance when viewed visually through glass slides and antireflective layers.

In order to evaluate the ability of the indicator to compete with microporous carbon for adsorption of organic vapor, the indicator was placed on a small piece of carbon loaded nonwoven web 94 used in Example 2. When equilibrated with 1000 ppm of cyclohexane flowing at 32 L / min, the carbon in the bed adsorbs 0.21 g of cyclohexane per gram of carbon. Indicator appearance was observed through a glass substrate using a spectrometer and a fiber optic reflective probe and measured in dry air (<3% RH) and at 85% relative humidity. The indicator showed only 3 nm spectral variation at 85% relative humidity compared to the results in dry air, thus indicating that the indicator was generally insensitive to high humidity conditions. The carbon loaded nonwoven web was then exposed to 20 ppm styrene vapor while maintaining an 85% relative humidity atmosphere. The indicator showed 23 nm spectral variation, demonstrating that the indicator maintained its adsorption function when in thermodynamic competition with microporous carbon exposed to wet analyte flow.

Example  9

Using the method of Example 6, a 10 nm thick titanium semireflective layer was evaporated coated onto two washed glass slides. PIM polymers having a weight average molecular weight (Mw) of 62,900 were prepared using the method of Example 3 and the monomers BC and FA. A 3.2% PIM polymer solution in a 60/40 chlorobenzene / tetrahydropyran mixture was spin coated at 1000 rpm onto the Ti layer of the coated glass slide. A dilution containing 16.8% solids by adding 1.0 g of SilverJet ™ DGP 40LT-25C silver nanoparticles (43.25% in methanol, Advanced Nano Products Company of Korea, LTD.) To 2 milliliters of methanol. Suspension was provided. The diluted suspension was spin coated at 600 rpm on a PIM layer on each coated slide. Then, one slide was air dried and called indicator A. The other slide was heated in air at 150 ° C. for 1 hour to partially sinter the silver particles, which was referred to as indicator B. Indicator B had a reflectance of about 39% at 500 nm for a 100 nm thick aluminum reference layer.

To evaluate the ability of both indicators to compete with microporous carbon for adsorption of organic vapor, the coated side of each slide was placed on the carbon used in Example 2 with the permeable nanoparticle reflector in contact with the carbon loading web. Placed against a small piece of charging web 94. The indicator was observed through a glass substrate and a semireflective layer using a spectrometer and a fiber optic reflective probe. The indicator was exposed to a 50 ppm toluene vapor stream through the carbon loading web. The spectral peak for indicator A varies from 532 nm to 558 nm and the spectral minimum for indicator B varies from 609 nm to 629 nm, in each case adsorbing when the indicator is in thermodynamic competition with the microporous carbon. It proved to be functional.

All patents and patent applications cited herein, including those cited in the background section, are incorporated herein by reference in their entirety. In case of conflict, the present specification shall control.

A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims (38)

A protective device comprising an enclosure comprising a gas inlet, a gas outlet, and a thin film multilayer indicator, the protective device comprising: A) The enclosure comprises an adsorption medium capable of adsorbing vapor of interest flowing from inlet to outlet; B) thin film multilayer indicator, i) a porous detection layer whose optical thickness varies in the presence of vapor, ii) a semi-reflective layer visible from outside the enclosure, iii) a reflective layer permeable to vapor, the porous detection layer being located between the semireflective layer and the reflective layer, C) The reflective layer is close enough to the medium so that when the vapor concentration applied between at least a portion of the medium and the vapor is in equilibrium, vapor passes through the reflective layer from the medium into the detection layer, thereby sufficiently reflecting the optical thickness of the detection layer, thereby causing antireflection. The device such that the indicator appearance can cause a visually discernible change when viewed through layers. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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